Answer:
Lixin obtains 15 marks
Step-by-step explanation:
Lets write two equations based on the question where: D= Devi and L=Lixin
D=L+15 - "devi scores 15 marks more than lixin"
D=2L - "devi obtains twice as many marks as lexin"
Now, substitute 2L as D in the first equation we wrote: (D=L+15)
2L=L+15
Next, subtract L from both sides:
L=15
